Portion of a display screen with a user interface



FIG. 1 is a front view of a portion of a display screen with a user interface showing the claimed design in accordance with a first embodiment; and,

FIG. 2 is a front view of a portion of a display screen with a user interface showing the claimed design in accordance with a second embodiment.

The portions of the user interface illustrated in broken lines form no part of the claimed design. The portion of the display screen is understood to be congruent with the shape of the user interface. 

The ornamental design for a portion of a display screen with a user interface, as shown and described. 